1. Field of the Invention
This invention relates to computer system tests and, more particularly, to a Basic Input/Output System (BIOS) test for determining when a Central Processing Unit (CPU) is being overclocked.
2. Description of the Prior Art
The term overclocking is used to describe the process of running the CPU or processor in a Personal Computer (PC) at a clock and/or bus speed higher than that for which it was designed or specified. The terms CPU and processor are used interchangeably in the foregoing description. The motivation behind overclocking a CPU is to increase system performance at very little cost, that is, without having to purchase a more expensive, faster CPU. Many times, overclocking is accomplished by merely changing a few settings on the PC""s motherboard. Other times, overclocking requires that additional components be added to the PCxe2x80x94primarily for cooling purposesxe2x80x94to achieve the sought after performance improvement.
Overclocking a CPU has several negative consequences for both end-users and CPU manufacturers. Overclocking generally degrades the reliability of a CPU because an overclocked CPU generally operates at higher temperatures than a CPU running at rated speed. The increased temperatures can trigger certain failure mechanisms, e.g., electromigration, which create physical defects in the silicon making up the CPU. These defects, over time, can cause the CPU to fail completely, reducing its useful life. The increased temperatures can also trigger operational failures because design parameters such as set up and hold times are not optimized. Overclocking increases the probability of a system wide failure that can lead to an irrecoverable loss of data. Worse yet, overclocking can result in intermittent CPU failures. Intermittent failures are difficult to track and fix because they are inherently difficult to duplicate.
Reliability degradation such as that described above reflects adversely on the quality of the CPUs produced by the CPU manufacturer. Resellers sometimes overclock CPUs without the knowledge or consent of the end user. End users have no easily discernable way of identifying an overclocked CPU particularly when the CPU contained in the system has been unscrupulously relabeled to identify it as a faster CPU. Moreover, overclocking negatively impacts the revenue of CPU manufacturers because resellers and end users purchase less expensive, slower CPUs for overclocking instead of purchasing more expensive, faster CPUs.
Accordingly, a need remains for a readily available internal system test that will allow end users to identify overclocked CPUs.